Infectious diseases remain an unsolved problem, due largely to emergence of multiply-antibiotic resistant strains of bacteria, newly discovered viral diseases, and the spread of fungal and protozoan diseases.
Advanced periodontal disease is one of a large number of oral infectious diseases, and is the principal cause of tooth loss in those over 30 years old. Periodontal diseases arise from the interaction between bacterial cells and their products in dental plaque, and the host defense mechanisms (Antczak-Bouckoms, A., (1994), J. Dent. Educ. 58:625-640). Current treatments often rely on mechanical removal of the plaque and bacteria, which can be inefficient (Unsal E. et al., (1995), J. Periodontol. 66:47-51), or antibiotic therapy, which can lead to bacterial resistance (Olsvik, B. et al., (1995), J. Clin. Periodontol. 22:391-396).
Photodynamic therapy (PDT) has been proposed as an attractive method of eliminating oral bacteria and bacteria in topical and gastrointestinal infections because these sites are relatively accessible to illumination. For example, fiber optics can be used to deliver light into the dental pocket (Wilson, M., (1993), J. Appl. Bacteriol. 75:299-306).